Perhaps UFOs are at the very heart of religion. A website that contains a wealth of well- documented information on this question can be found at The Bible UFO Connection website (see related link)
The instant they are found they cease to exist. They are found and then they are identified. Once identified they cease to be UFOs.
It is impossible to even speculate. There is no admitted proof that UFOs do exist and no hard information on propulsion.
Extraterrestrial life forms-if they exist.
No accurate records exist.
No accurate records exist.
Yes.... People have seen UFOs.
Roswell Yes and Ufo's No
No, but most believers don't need proof.
No accurate records exist.
No they don't, and you ever tells you they do are lying
UFOs are neither good nor bad . . . they are simply things we see in the sky that we do not recognize. That is why they are called "Unidentified" flying Objects (UFOs). If you mean, aliens from another star system, they do not exist in our Solar system, so cannot be either good or bad.
How much a UFO would weigh if they do indeed exist is not known.